Cate --
No I don't think they're too small. I do remember having a box w/ cards when I was young and single (eons ago!). Somehow as I became more used to cooking/baking I liked having either a book or a recipe sheet.
I started buying cookbooks (small paper backs and large hard covers) plus getting cookbooks out of the public library.
Now, of course, many of our favorites are saved in my computer - under different categories, types, etc. But I still have umpteen 3 ring binders of recipes I've typed (before I was into computers) and printed off from sites and newspaper food secitons, magazines, etc. And cookbooks! I have bookcases in 3 bedrooms and in the dinette! Plus I have some boxes of clippings and such .. that I'm trying to sort-through. I've sold and/or given away hundreds .. but they still accumulate and multiply --- like rabbits! I'll probably be 115 before I sort them all out .. but I work at it!
I do have some cards .. its just NOT MY favorite way. I have friends that love cards. But I find the ones in these small books just are not my thing. But occasionally I'll buy one if I HAVE to have something!